In the growth of children, toys will bring them many beneficial experiences and happiness. If the toys, however, are of low quality, then no happiness, or even harm will be brought to the children. The safety problem of catapulting toys is particularly concerned. In the prior art, enhancing the strength of a projectile (enabling the projectile to pass through a tensile test)/shortening a stroke or connecting with a safety valve from a launching cylinder to control exhaust through the projectile is usually used in terms of the safety problems of catapulting toys.